Spark arrester silencer



Dec. 9, 1941. R. B. BOURNE 2,265,343

SPARK RRESTER SILENCER Filed Aug. 4, 1940 Patented Dec. 9, 1941 SPARK ARIRESTER SILENCER y Roland B. Bourne, Hartford, Conn., assigner to The Maxim Silencer Company, a i-corporation-of Connecticut Hartford, Conn.,

Apicati'iahgust 4, 1940, serial No. 351,415

(ci isi-cs) 3 Claims.

The present invention pertains to devices for silencing the exhaust noise of internal combustion engines and the like, and at the same time removing from the exhaust gases all the entrained dirt, sparks, and the like.

The invention as disclosed accomplishes these results with very low back-pressure, even though devices of this type may be made with relatively low volumetric capacity. I have made successful devices after the teachings of my invention which are of relatively small size in comparison to devices heretofore used.

The invention involves the use of a. retroverted gas flow type of silencer so constructed that the outlet tubes from the silencing chamber give the exhaust gases 4an upward whirling motion as they enter the dirt separating chamber, wherein the dirt and sparks are removed as will be hereinafter described. The exhaustr gases pass out through a coaxially disposed outlet connection having anti-whirl means positioned therein.

For a complete description of my invention, I refer to the drawing, wherein,

Fig. 1 is a side view of the device, partly broken away;

Fig. 2 is a transverse section on line 2--2 of Fig. 1. f

Referring to Fig. 1, the device comprises a generally cylindrical casing I having an inlet header II and an outlet header I2 with inlet and outlet openings I3, I`4 disposed therein respectively. A transverse rheader I5 divides the lnterior of the casing into a lower silencing chamber IB and an upper dirt separating chamber I1. Extending from the centrally disposed inlet opening I3 into the interior of the chamber I6 is the pipe I8, the open end of which terminates at a point in adjacency to the transverse header I5, The pipe I8 is provided with a slot I9 whereby is secured some gas and sound wave leakage into the chamber I6. This slot, which may be replaced by a series of perforations without prejudice to the operation, of the device, preferably has a width of the order of one twentieth the pipe diameter. The gases pass from the chamber I6 into the chamber Il through the four pipes which are equally spaced around the inner periphery of the chamber I6 and have their bottom open ends in adjacency to the inlet header II. The pipes 20 are bent to an angle of about 45 degrees at their upper ends and thus provide a whirling motion for the exhaust gases as they leave the'pipes 20 through the elliptical apertures 2| in the transverse header I5. The

upper ends of the bent pipes 20 are flush with 55 the surface of the header ISQIn .ordervtggprevent the pipes 20 from soundingjofff4 due to shock excitation, they are provided with small "apertures 22 positioned at points along their lengths substantially equal one half and one quarter the length of the pipes after the manner disclosed in my co-pending patent application Serial No. 291,820 filed August 25, 1939.

The upwardly whirling dirt-bearing gases throw the entrained dirt out against'the inner smooth wall of the separating chamber I 1 whence they eventually fall into the dirt collector tube 23 through the vertical row of apertures 24. The collected dirt falls unhindered into the dirt box 25 from whence it may be removed when necessary. y

The exhaust gases having been freed of dirt now pass out through a co-axially disposed outlet fitting 26 which projects into the interior of the chamber I1 through the outlet opening Il, and expands outwardly into the chamber I1 in the form of a conical skirt 21. The conical section 21 vis fitted with longitudinally disposed vanes 29, at least the lower edges of which are preferably curved to form scoop-like entrance vanes 30 whereby the whirling gases present below the lower end of the unit 21 are readily taken into the outlet unit and the whirl eliminated therein. This feature results in a great reduc tion of back-pressure. The conical surface 21 of the unit 26 prevents any dirt particles present in the upper end of the whirl chamber I1 from working down to the open end of the outlet unit 26 whence they might otherwise be carried into the outlet exhaust gas stream. The diameter of the skirt 21 should be as large as possible in the interests of low back-pressure but not so large as to interfere with the proper dirt separating action of the Whirl chamber.

It will be seen that the device as a whole is a highly compact and efcient spark arrester silencer. The use of the inclined silencing tubes as gas whirlers eliminates the necessity for separate gas whirling means. A very vigorous whirl is given the gases, resulting in efficient cleaning. The high back pressure ordinarily associated with rapidly whirling gases in a chamber is reduced to about one quarter or less of its former value by the use of vanes structure in the outlet connection. This advantage is directly reilected in the smaller diameter of the whirl chamber thus made possible.

I claim:

1. A spark arrester silencer comprising a generally cylindrical vertical casing divided by a transverse partition positioned at an intermedi` ate point along its length into a lower silencing chamber and an upper dirt separating chamber, said silencing chamber'having an inlet conduit extending from an inlet opening thereinto to a point in adjacency to said transverse header, one

or more conduits bent at their upper ends at-" tached to and depending from said transverse header at outlet openings therein into said silencing chamber so, as to form a silencer of the retrogressive gas ilow type, the upper ends of said open ended bent conduits being flush with the surface of said transverse partition whereby an unimpeded whirling motion of gases in said separating chamber may take place, 'dirt collecting means associated with said dirt separating chamber comprising an exteriorly disposed longitudinal tubular member having a dirt .box at its lower end and being completely closed except for one or more aperturesy in the wall of the cylindrical casing through which dirt particles may pass from said` dirt separating chamber into said exteriorly disposed tubular member. and a gas outlet connection comprising an open conical member projecting into the interior or saidy whirl chamber and having disposed within said conical member one or more anti-whirl Vanes.

2. A spark arrester silencer comprising a generally cylindrical silencer chamber and a generally cylindrical dirt separating chamber in axial alignmentl therewith, a gas inlet pipe entering and extending a substantial distance into the silencer chamber, a plurality of open-ended conduits opening into the dirt separating chamber and extending a substantial distance into the silencer chamber, said conduits having lateral openings within the silencer chamber and having their portions adjacent the dirt separating chamber arranged in a generally helical manner to impart a whirling motion to the gases, and one or more dirt escape openings formed in the Wall of the dirt separating chamber.

3. A spark arrester vsilencer comprising a generally cylindrical silencer chamber and a generally cylindrical dirt separating chamber in axial alignment therewith, a gas inlet pipe entering and extending a substantial distance into the silencer chamber, a plurality of open-ended conduits opening into the dirt separating chamber and extending a substantial distance into the silencer chamber, said conduits having lateral openings within the silencer chamber and having their portions adjacent the dirt separating chamber arranged in a generally helical manner to impart af whirling motion to the gases, one or more dirt escape openings formed in the wall of the dirt separating chamber, a gas discharge conduit opening out of the dirt separating chamber and positioned substantially axially thereof, the portion of the discharge conduit within the dirt separating chamber being formed as a cone converging towards the outlet, and a plurality of radial vanes within said cone concave towards thefoncoming whirling gas.

ROLAND B. BOURNE. 

